Blow-off valve



G. F. GERD'I'SV Oct, 25, 1932.

BLOW-OFF VALVE Filed Jan. 28. 1931 l INVENTU Patented oct. 25, 1932 PATENT oI-Flclaz yG'rUSTAV FRIEDRICH GERDTS, OF BREMEN, GERMANY g BLOW-OFF VALVE Application filed-January 28, 1.931, Serial No. 511,877, and in Germany January 29, 1930.

The invention relates to devices `for blowing-off steam boilers and similar purposes.

Of the spindle and automatic or check valves so far employed for blowing-off steam boilers, only check valves are considered quick acting. As-such check valves are held closed mainly through the pressure within the boiler, they are not to be depended upon in practice for obtaining and maintaining an absolutely reliable, tightseat, for which reason the provision of an additional or` auxiliary, for instance a screw valve, has been mayde obligatory.

,On the other hand, in the case of spindle valves, so much time is required for effectively screwing the disks or cones of the same off and onto their seats as to make it practically impossible to blow-off rationally and economically with the same, which can only be done if the valve is opened comparatively often, and then for not longer than from 1 to 2 seconds each time, as is now well understood. l

The particular object of my invention is to overcome these deficiencies, mainly by providing additional or supplementary valve operating means and in this manner produce a combined, quick acting and also positively and reliably closing, so-called safety blow-0E valve,.preferably in a one-part casing having one seat only and in such a manner that its single, plain spindle is, as may be found advisable, either operatively reciprocated in a direct manner by a lever and a spring thereon, or similarly reciprocated, independently thereof, by means of a hand-wheel-turned screw, in the latter case also without in any way turning the valve spindle.

The new valve is to be quickly opened by suitably depressing the lever, and quickly closed by spring action, in a manner as is well known, and according to the invention the valve can then be tightly sealed by the action of a-screw against a. projection on the valve stem, through which the valve is forced" tightly against its seat, whilst, whenever the boileris to be emptied, the valve when acted upon in the opposite direction can be opened and held open by the screw when correspondingly acting against a further projection on the valve spindle, the lever and the screw not in any way interfering with each other in or by their separate and different operations.

To this end I provide, according to the inl vention, on the yoke or another part of the valve body and adapted to limitedly screw in the same, in both directions, an externally threaded sleeve or bushing in the central bore of which the spindle, when acted upon, whether by the lever or by the hand wheel, 6o can slide and reciprocate axially to an extent limited by and between two projections or stops on the valve stem, of which one is for instance above the sleeve in the form of a cap at or nearv the free end of the stem, and the other for instance below the sleeve in the form of a collar, whichlatter projection is preferably also in operative engagement with the lever, for instance through a bifurcated part of this lever.

By means of substantially such an arrangement of a single valve independently operable by two entirely different devices for `reciprocating the valve stem, by either a lever or by a screw, the auxiliary screw operated device comprising a sleeve axially limitedly screwing in the valve casing between two projections or stops on the valve spindle, a quick acting safety blow-ofi' valve is obtained by means of which mud and caustic solution can be removed from boilers most satisfactorily, with the least loss of hot water.

My improvements are shown in the accompanying drawing in cross section, partly in section.

The yoke a of the valvebody or casing b is centrally bored and threaded to receive and revolubly operatively support 4the externally4 threaded sleeve or bushing c, in the central bore of which latter the valve stem or spindle d with valve head lc at its endV is. adapted to longitudinally slide andv reciprocate during operation.

A collar, as f, is secured to spindle d and pivotally engages with, or is engaged by, a bifurcated part of the lever h', a spring, as z', serving to return the valve to its seat and to maintain it closed.

.The valve stem is provided at its free end with a projecting cap or stop, as e. However,

gland nut mis also adapted to limit the opening movement of the valve stem. A cheek valve, as j returned and held to its seat by spring Z, may be provided to afford security in ease of an accident to the spindle valve.

In operation, lever h is depressed to blowof the boiler and is supposed to be released Within 2 seconds, the spring e' thenreturning the valve to its seat and the Valve being automatically moved to its seat. Should the valve not be closed reliably tight thereby, sleeve c, by being screwed so as to press against cap e, will force the valve against its seat, obviously with the result of absolutely sealing the valve.

On the other h'and, screwing valve sleeve o against the upper part of collar f, the valve can be opened and maintained open, whereby any emptying of the boiler is greatly facilitated.

My improvements are of simple and practical construction and most effective in operation and may also be used in connection with other than blow-off valves. It is to be observed also that while I have herein given a detailed description of the two diii'erent mechanisms for actuating one and .the same Valve spindle, others may aswell be employed Without departing from the invention.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a lever-operatedvalve having a reciprocatable valve spindle, auxiliary operat ing means axially screwable in\the valve easing for independently reciprocating the valve spindle,

2. In a blow-ofi' valve a lever-operated spindle for normally opening the valve, in combination with a sleeve axially screwable in the casing, the 'spindle being adapted t0 axially reciprocate in the sleeve and being also provided with a projecting stop near each of the two ends of the sleeve, by means 4 of which the valve may be screw-operated by Athe sleeve.

3. In a lever-operated blow-ofi1 Valve, means for normally holding the valve in closed position, an externally threaded sleeve or bushable in thecasing and projections on the valve stem to be operatively alternatingly engaged by the sleeve when turning, in one direction to tightly seal the closed valve and in the other direction to open and to maintain open the valve respectively, without turning the valve spindle.

5. In a lever operated blow-oit' valve, an externally threaded, hand-wlieel-turned sleeve or bushing screwable in the valve casing, a valve'stem centrally slidable in the sleeve, a collar on the valve stem pivotally engaged by the lever and engageable by the sleeve to serew-open the valve and a cap at the free end of the valve stem engageable by the sleeve to tightly seal the valve closed.

In testimony whereof I aflix my signature.

GUSTAV FRIEDRICH GERDTS. 

